Heya everyone! First post here, and as the title suggest I was looking for some insight on legacy life since I've only ever been at a regional (Endeavor: 1.5 yrs of service). Would like to first say thank you to everyone that gives their advice, negative or positive, as its invaluable for someone with minimal experience in the industry such as myself (23 yr old, born/raised in IAH, currently living in FL, single, open to living in FL or TX rest of my career.. the commute FL - ATL is doable, but one thing I've learned living in base is invaluable. *No interest in commuting any further north than ATL/further west than IAH the rest of my career).
I'm about to start United training, but just received a DL CJO. I'm aware of contract volatility at UA, and am doing my best to weigh that as a short term issue (not too concerned about it). Though, outside of contract, I like to think I'm familiar with the DL brand and have had a great ride at Endeavor, and am excited to experience the UA brand. WB flying is def something I'd like to spend majority of my career doing, but IAH 737 has been recommended initially to me in FB groups as you can break seat locks, gain exp, upgrade in base, etc. From what I've gathered DL's sonority movement long term is slower, they've hired more than UA ahead of me, less retirements, and have one southern base where WB seniority would be difficult accumulating. On the other hand, UA is rapidly gaining aircraft, hiring more than DL, expanding, much better network (DL love of codeshare seems no fun), and caters to southern pilots much better than DL, base wise.
It seems unnecessary to put all my concerns/questions in one post, so that's my paragraph. Overall, I'd like to hear opinions from those who have lived the legacy airline life. Any guidance you have to offer would greatly help as these are two great airlines, and I'm trying my best to gather information from all sources to make a career long decision!

Thank you all, and take care!